Use s:placeholder to keep track of lost color in _high schemes

colors/solarized8_dark_high.vim

@@ -131,6 +131,7 @@ if has('nvim')
   let g:terminal_color_7 = '#eee8d5'
   let g:terminal_color_8 = '#002b36'
   let g:terminal_color_9 = '#cb4b16'
+  let g:terminal_color_10 = '#586e75'
   let g:terminal_color_11 = '#657b83'
   let g:terminal_color_12 = '#839496'
   let g:terminal_color_13 = '#6c71c4'

colors/solarized8_light_high.vim

@@ -135,6 +135,7 @@ if has('nvim')
   let g:terminal_color_11 = '#657b83'
   let g:terminal_color_12 = '#839496'
   let g:terminal_color_13 = '#6c71c4'
+  let g:terminal_color_14 = '#93a1a1'
   let g:terminal_color_15 = '#fdf6e3'
 endif
 hi! MatchParen cterm=NONE,bold gui=NONE,bold ctermfg=15 guifg=#fdf6e3 ctermbg=11 guibg=#657b83

src/solarized8.vim

@@ -46,6 +46,7 @@ for s:solarized_background in ["dark", "light"]
     let s:b           = ",bold"
     let s:i           = ",italic"
     let s:u           = ""
+    let s:placeholder = ["",""]
 
     if s:solarized_background == "light"
       let s:temp03      = s:base03
@@ -64,6 +65,7 @@ for s:solarized_background in ["dark", "light"]
     endif
 
     if s:solarized_contrast == "high"
+      let s:placeholder = s:base01
       let s:base01      = s:base00
       let s:base00      = s:base0
       let s:base0       = s:base1
@@ -486,7 +488,8 @@ for s:solarized_background in ["dark", "light"]
           \ s:violet,
           \ s:blue,
           \ s:cyan,
-          \ s:green
+          \ s:green,
+          \ s:placeholder
           \ ]
     let s:colorTableIndices = map(copy(s:colorTable), 'v:val[0]')
     let s:colorTableCodes   = map(copy(s:colorTable), 'v:val[1]')